A microwaveable food carton comprising an integral, mid-elevation food supporting panel having a sheet of microwave interactive material placed on one surface is disclosed in U.S. Pat. No. 4,836,383, Microwave Food Carton With Divider Panel which patent issued June 6, 1989 to Gordon et al. Essentially, the construction of the carton is such that food contained within the carton is elevated above the carton bottom on a false bottom: i.e., the mid-elevation food support panel. Thus, the microwave interactive material on the mid-elevation food support panel causes the support panel to have a hot plate heating effect on the food supported thereon. The function of the microwave interactive sheet is stated to be to brown or crispen the contacted surface of the food product.
A microwaveable food package and carton therefore comprising microwave susceptors (i.e., materials which are heated by internally generated heat when subjected to microwave energy) for browning and crisping two sides of food pieces contained therein is disclosed in U.S. Pat. No. 4,590,349, Microwave Cooking Carton For Browning And Crisping Food On Two Sides which patent issued May 20, 1986 to Brown et al. It is specifically directed to browning and crisping two sides of food pieces having non-uniform dimensions; the carton has an internal height exceeding the average vertical height of the food pieces; and it states that the package be inverted during the microwave heating cycle to cause the food pieces to gravitationally contact a final food support panel disposed in the top portion of the carton.
Additional U.S. Patents which disclose microwave food packages and browning of foodstuffs packaged therein include: U.S. Pat. No. 4,190,757, Microwave Heating Package and Method which issued Feb. 26, 1980 to Turpin et al; U.S. Pat. No. 4,267,420, Packaged Food Item And Method For Achieving Microwave Browning Thereof which issued May 12, 1981 to Brastad; U.S. Pat. No. 4,594,492, Microwave Package Including A Resiliently Biased Browning Layer which issued June 10, 1986 to Maroszek; and U.S. Pat. No. 4,777,053, Microwave Heating Package which issued Oct. 11, 1988 to Tobelmann et al.
Further disclosures of microwave cartons, packages, and susceptors are included in the following U.S. Pat. Nos: 4,641,005 and 4,825,025, both titled Food Receptacle For Microwave Cooking, which issued Feb. 3, 1987 and Apr. 25, 1989, respectively, to Oscar E. Seiferth; and U.S. Pat. No. 4,230,924, Method And Material For Prepackaging Food To Achieve Microwave Browning which issued Oct. 28, 1980; and U.S. Pat. No. 4,864,089, Localized Microwave Radiation Heating which issued Sept. 5, 1989 to Tighe et al. Tighe et al (4,864,089) disclose formation of microwave susceptor areas on suitable substrates by coating or printing a resin binder with conductive and semiconductive particles.
Microwave susceptor technology is discussed further in Microwave Susceptor Use Continues To Be Hot Topic, Paper, film & Foil Converter, January 1989, pages 62-64, inclusive. Additionally, parfrying technology, which is considered to be ancillary to the present invention, is disclosed in U.S. Pat. No. 4,590,080, Process For Preparing Parfried And Frozen Potato Products which issued May 20, 1986.